Our previous studies have indicated that there may be a functional relationship between benzodiazepine (BZ) receptor stimulation and alterations in calcium flux. We reported last year, for instance, that nifedipine, a calcium channel blocker, would present the sleep-inducing effects of flurazepam in rats. We have shown that BAY K 8644, a calcium channel agonist, enhances the sleep-inducing properties of flurazepam.